Chapter 2 – Chemistry Test Questions – Flashcards

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four molecules that make up 96% of living organisms
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hydrogen (H) Carbon (C) Oxygen (O) and Nitrogen (N)
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what is matter?
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anything that occupies space and has mass
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what is mass?
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the quantity of matter an object has.

mass is not the same as weight

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elements
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pure substances that connot be broken down chemically into simpler kinds of matter

each element has a specfic symbol, which consists of one or 2 letters, called its chemical symbol

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atoms
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atoms are the simplest unit of an element that retains all the same properties of that element

consists of 3 distinct parts called subatomic particles

the center of the atom is called the nucleus

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nucleus
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composed of 2 subatomic particles: protons and neutrons

protons have positive charge

neutrons has neutral charge (no charge)

consists of the mass of the atom

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protons
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the number of protons= atomic number

# of protons identifies the element

the positive charge of the proton is balanced by the negative charge of the electron

 electron energy levels: those in the outermost layer have more energy than ones in the inner levels


 

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electrons
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surrounding the nucleus is the elcectron cloud

has a negative charge and constanly move around the nucleus

the mass of the electron is so small that it is not even considered when calculating the mass of an atom

 

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neutrons
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nuetrons= atomic mass= atomic number
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atomic number
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# of protons
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atomic weight
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protons + neutrons
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valence electrons
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the electrons in the outermost level are called valence electrons

the valence electron will determine how an element will behave chemically

 

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compounds
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pure substance made up of two or more elements

Ex: NaCl

Sodium Chloride :)

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molecule
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is the simplest part of a substance that retains all of the properties of the substance and can exist in a free state
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chemical bonds
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the sharing or transferring of electrons b/w two electrons

(how molecules are made)

2 types of bonding: covelant and ionic

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covalent bonding
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formed when two atoms share one or more pairs of electrons

(may have single, double or triple bonds between atoms)

 

Some covalent bonds form polar molecules, which mean that they have a slightly positive and a slightly negative side.

 

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polarity
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the oxygen region is slightly negative

hydrogen region is slightly positive

atoms are not arranged in a staright line

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ions
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an atom that has lost or gained an electron in it outer shell (very unstable) and now carries a charge.

 

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ionic bonding
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formed when electrons are gained or lost
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cation
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a postively charged ion
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anioin
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negitavly charged ion
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hydrogen bonding
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bond between hydrogen atoms already covelantly bonded in a molecule to oppositely charge particles (water molecules)

weak bond that can be easily broken

causes water to cling to itself


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chemical reaction
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simply the making and breaking of bonds
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chemical equation
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the way a reaction is described in writing

has 3 basic components: reactants, products and arrow

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reactants
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the ions or molecules that go into the reaction
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products
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the outcome of the reaction
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arrow
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describes the direction the reaction is going
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3 types of chemical reaction
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sythesis, decomposition, and exchange
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synthesis reaction
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building a more complex molecule from many simple ones

Requires energy

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decomposition reaction
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a more complex molecule broken down into many smaller ones

releases energy

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exchange reaction
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atoms are exchanged between molecules

energy is not required or released.

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what factors influence the rate of chemical reactions?
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catalysts, temperature, concentration, and surface of the reactants
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catalysts
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is a protein

is destroyed or used up during a reaction

speeds up the reaction

AKA and enzyme

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inorganic molecules
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does not contain hydrocarbon groups

often has ionic bonding

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solutes
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substances that are being dissolved
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solvent
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the liquid that dissolves the substances
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solution
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mixture of the solute and the solvent
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concentration
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a measurment of the amount of solute dissolved in a fixed amount of solution

 

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saturated solution
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a solution in which no more solute can dissolve
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hydrophilic
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water loving (usually polar molecules or ions that dissolves or mixes well with water)
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hydrophobic
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water hating (usually neutral, non polar molecules such as lipids)
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electrolytes
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salts in their ionic form that have the ability to trasmit an electrical charge
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dissociation
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the breaking apart of a water molecule into 2 ions of opposite charge (does not equal ionization)
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ionize
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ionically bonded substances, that when added to water, it breaks apart into their invidual ions
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acids
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1 to 6

if the number of hydrogen ions in a solution is greater than the number of hydroxide ions, the solution is acid

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bases
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5 to 14

if the number of hydroxide ions is greater than the number of hydronium ions, the solution is a base

base=alkaline

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neutral
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7

blood=7.4

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buffers
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chemical substances that neutralize small amounts of acids or bases

helps to maintaim pH of body fluids at normal levels

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organic molecules
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conatins hydrocarbon groups whuch are made up of carbon atom carbon atoms covalently bonded to other carbon atoms, hydrogen, oxygen and nitrogen

divided into 4 groups: carbs, protein, lipids, and nucleic acids

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